In recent years, electrophotographic copying apparatuses have been receiving demands for smaller size, saved space and higher speed.
A conventional electrophotographic copying apparatus is explained below in conjunction with the drawings In FIG. 6, there is disclosed an electrophotographic copying apparatus which comprises a first unit 111, a second unit 112, a third unit 113 and a control panel 114, wherein the first unit, the second unit and the third unit are stacked one on another The first unit includes optical elements such as an exposure lamp 115, reflecting mirrors 116 and lenses. The second unit includes a photosensitive drum 117, a developing device 118, a cleaning device 119, a transfer device 120, a fixing device 121 and the like. The third unit includes a sheet feeder 122. The second unit and the third unit can be pulled out rightward in the figure, so that the electrophotographic copying apparatus is small-sized and space-saving, while keeping easy in maintenance and jam-processing (Japanese Laid-Open Patent Publication No. 4-371964).
These photosensitive drum, developing device and cleaning device of the electrophotographic copying apparatus are so arranged that a developing roller 124, the photosensitive drum 117 and the cleaning device 119 are integrated into a developing frame 123 as shown in FIG. 7 so as to be used as fittable to and removable from the copying apparatus Reference numeral 125 denotes a drum shaft, 126 denotes a side plate and 127 denotes a development cover 127 (Japanese Patent Publication No. 60-59591).
However, in the above conventional constitution, the first unit includes the optical elements is equal in vertical size for all parts, such that the box dimensions of the unit depends on the way the optical components are placed, with the result that even if useless space is involved, the unit would be stacked on as it is. The second unit is given as an image-formation processing unit, whereas fixing device is also arrayed horizontally besides the photosensitive drum, the developing device and the cleaning device, such that the unit size is lengthened in the direction of array, inevitably causing the whole apparatus to increase in size. Therefore, because a fed sheet is conveyed along the array of the image-formation processing unit, the conveyance path would become long, resulting in longer copying time.
Furthermore, because the image-formation processing unit including the development frame is weighty, the component members involved are arranged so as to be retained by metallic side plates in order to meet the weighty article and the placement relationship that requires an accurate positioning Therefore, the whole second unit would be heavy, such that the whole apparatus would also be heavy.
The present invention has been accomplished to solve the foregoing issues, and an object of the invention is to provide an electrophotographic copying apparatus which is made more compact and shorter in copying time by disposing its component units vertically, and moreover which is reduced in weight by incorporating a resin frame molding